The modern surgical orientation (surgery is the only therapy that ensures real results in patients who have exceeded obesity values close to, or in excess of, 40 BMI, i.e. the ratio of weight to the square of the height) entails the reduction of gastric compliance, with the aim of limiting the subject's ability to ingest food, or of reducing the food absorption surface by shortening or bypassing part of the digestive canal; both aims are sought in some surgical procedures.
All of the surgical procedures currently in use have some immediate and/or delayed risks and surgery must thus be considered as an extreme solution.
Furthermore, even surgical treatment fails sometimes, since the patient becomes obese in or the complications are such as to force the surgeon to restore the original anatomical situation, with the consequence of failing to achieve the intended aim of reaching the ideal weight.